Author: Sune Fischer
Date: 11:39:07 03/09/03
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On March 09, 2003 at 00:49:38, Robert Hyatt wrote: >On March 06, 2003 at 08:27:26, Georg v. Zimmermann wrote: > >> >>> >>>I don't see any reason to extend a move I fail high on, unless there is a threat >>>further down. > >The problem is that often you have _one_ good move. All others fail low, >and this _one_ move seems to be good enough and fails high. But if you >go deeper, you see it fail also and don't make a mistake. Hence the point >for singular-extensions. When you have lots of good moves, if you discover >one is bad, that's ok, you have plenty of others. But once you know there >is only _one_ good move, it had _better_ be good or the entire path gets >mis-evaluated. So you mean if one move just barely fails high, and all the others don't even reach alpha, then extend to make sure we really are failing high here? >>>Extending singular moves like PxQ where there is no threat involved is a waste >>>of time as far as I can tell. > >You can avoide such extensions pretty easily. IE gross winning captures don't >need to be extended most of the time. Ditto for recaptures. I think happens in most of the cases, your opponent moved Qd5, you had a pawn on c4, now you have one good singular move but the whole position is rendered trash and you ought to fail high here instantly and not extend at all. That is unless you extend to make sure that eating the queen is not going to mate you, so it becomes sort of a threat verification search, only I think it would suck at this because most of the time there is no threat at all. Maybe if the fail high margin is too high, don't treat it like a singular move, is that what your saying? Maybe this could be made to work, it just makes it rather fuzzy what a singular move really is then, having a margin on both sides (not non-singular and not over-obviously-singular either!:). -S.
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